A by-wire vehicle brake system that makes a slave cylinder generate a brake fluid pressure responding to a stroke of a brake pedal is well-known. Relating to such a vehicle brake system, a well-known technique for improving a brake feeling of a driver (feeling of secureness for braking effect, actual feeling that the brake is working well) is disclosed by, for example, Patent Document 1.
Patent Document 1 discloses a technique of selecting either one of a normal map and a build-up map for setting a brake fluid pressure reference value larger than that of the normal map to set the brake fluid pressure reference value on the basis of the map selected.